User experience is an important factor in the design of computing products (e.g., smart phones, media tablets, smart televisions, laptop computers, and so forth), and people usually prefer to purchase devices with improved user interfaces (UIs). Given the importance of user experience, many compelling UIs have been incorporated in personal mobile devices and electronic devices in recent years providing human-machine interaction, including, for example, body control, hand/finger gesture, voice command, facial expression, and the like. For example, touch screen UIs provide click, zoom in/out, rotate (two point touch), fling, scroll and the like. Though many existing products provide long-range touch-free gesture control (e.g., game consoles employing body control and the like) or touch-screen gesture control, conventional products do not incorporate short-range touch-free gesture control.